sale of second home 1099 S

I need help completing my 2021 taxes

I sold a second home I have had long term, it is not my primary residence

past 5 years was used by step son free

I have my initial cost basis at time of purchase 1997

1099 S has my gross proceeds

I have my seller statement.

I have receipts for improvements and additions which I want to use to increase my cost of home

where do I add the figures for my improvements to the cost basis (home purchase cost + improvement cost) the program is not very clear on this.

thank you.